This invention relates to polydiene resins and more particularly to polydiene resins having either urethane or epoxyl groups.
For a variety of applications (e.g. deep sea buoyancy structures, aviation structures, etc.) low density plastic resins having high compressive yield strengths are needed. The state of the art teaches that functionally terminated 1,2-polybutadiene resins, which are chain extended with a diisocyanate or diepoxide, may exhibit a low density and a remarkable ultimate strength exceeding that of many other high strength plastic materials. However, these resins lack high yield strengths and high elastic moduli.
For example, resin composite obtained from dihydroxyl 1,2-polybutadiene and toluene-2,4-diisocyanate had, after ring closure and/or crosslinking with a peroxide, a density of 1.04 and an ultimate compressive strength of 38,400 psi but a yield strength of only 5,500 psi and a compressive modulus of 225,000 psi. By comparison, a conventional epoxy resin had a density of 1.24, an ultimate compressive strength of 21,000 psi, a yield strength of 18,000 psi, and a compressive modulus of 500,000 psi. However, because conventional epoxy resins have high densities, they are less desirable for aviation or deep sea buoyancy structures than the low density polydiene resins. Therefore, it would be desirable to find novel low density polydiene resins having higher yield strengths than the prior art low density polydiene resins.